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September 8, 2005

Fossils Reveal Flying Prehistoric Giants

by Sam Savage

DUBLIN -- The giant reptiles that flew above the earth until about 65 million years ago could have grown to twice the size originally thought with wingspans of at least 18 meters, a paleontologist said on Thursday.

That would be almost the same width as the 64 foot fully extended wingspan of an F-14 Tomcat fighter aircraft and roughly five times bigger than an albatross, which ranks among the birds with the largest wingspans in the modern world.

Dr David Martill of the University of Portsmouth in southern England, said his research on pterosaur wings appeared to solve the problem of how such enormous creatures managed to take to the skies and stay there.

Recent fossil finds in Mexico and Israel added weight to the theory that this prehistoric, flying reptile, which became extinct at the same time as the dinosaurs, could have been much bigger than many had realized.

"We haven't officially announced this yet but it might have been two times bigger," he told journalists at the British Association for the Advancement of Science's annual festival in the Irish capital.

"BIG FRAGMENTS"

Martill said fellow academic and collaborator Dr Eberhard "Dino" Frey of the Natural History museum in Karlsruhe, Germany, had recently found distinctive fossilized footprints in Mexico pointing to a creature with a wingspan "in excess of 18 meters (60 ft)."

"Even though they are just fragments they are bloody big fragments," he said of the fossils. "We also have finger bones with really rather magnificent diameters."

Despite its size, Martill believes his studies of the bone structure and tissue of a pterosaur wing show it could have flown "really rather elegantly."

"The wing membrane is really very, very thin," he said, adding that the samples were about half a millimeter thick. "One of the other things we found out that was excitingly new was a very different shoulder joint."

The elaborate structure of the wing, more like that of a bat than a bird, combined with hollow bones and a body not much bigger than a human torso would have kept weight to a minimum.

"One imagines that the take off problems were less ... particularly if you add the fact that they were very, very lightly constructed to this enormous wing membrane area."

Martill said he had established that the wing was locked into the bottom of the body rather than the top, providing a greater surface area to benefit from the thermal air currents that give lift during flight.

More cumbersome would have been the neck, stretching to three meters in length and attached to a skull that could have added an additional two meters. Although not very aerodynamic, it might have allowed the pterosaur to pick up prey from the sea without flying dangerously close, Martill suggested.

As for why they grew so big, it could have been a function of age: "One of the reasons might be that they just kept on growing," rather than reaching an adult size when growth stops.